Endoscopic cap electrode and method for using the same

ABSTRACT

An apparatus for treating tissue in a tissue treatment region. The apparatus can comprise an electrode ring having an interior perimeter and an electrode probe having a proximal end and a distal end. The distal end of the electrode probe can be structured to axially translate relative to the interior perimeter of the electrode ring. The electrode ring and the electrode probe can be operably structured to conduct current therebetween when at least one of the electrode ring and the electrode probe is energized by an energy source. Further, the energy source can be a Radio Frequency (RF) energy source, a pulsed energy source, an irreversible electroporation energy source, or a pulsed irreversible electroporation energy source. A current from the energy source can be selected to non-thermally ablate tissue in the tissue treatment region.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application claiming priority under35 U.S.C. §120 to U.S. patent application Ser. No. 13/540,850, entitledENDOSCOPIC CAP ELECTRODE AND METHOD FOR USING THE SAME, filed Jul. 3,2012, now U.S. Patent Application Publication No. 2014/0012247, theentire disclosure of which is hereby incorporated by reference herein.

FIELD OF TECHNOLOGY

The present invention generally relates to surgical devices and methods.

BACKGROUND

Traditional, or open, surgical techniques may require a surgeon to makelarge incisions in a patient's body in order to access a tissuetreatment region, or surgical site. In some instances, these largeincisions may prolong the recovery time of and/or increase the scarringto the patient. As a result, minimally invasive surgical techniques arebecoming more preferred among surgeons and patients owing to the reducedsize of the incisions required for various procedures. In somecircumstances, minimally invasive surgical techniques may reduce thepossibility that the patient will suffer undesirable post-surgicalconditions, such as scarring and/or infections, for example. Further,such minimally invasive techniques can allow the patient to recover morerapidly as compared to traditional surgical procedures.

Endoscopy is one minimally invasive surgical technique which allows asurgeon to view and evaluate a surgical site by inserting at least onecannula, or trocar, into the patient's body through a natural opening inthe body and/or through a relatively small incision. In use, anendoscope can be inserted into, or through, the trocar so that thesurgeon can observe the surgical site. In various embodiments, theendoscope may include a flexible or rigid shaft, a camera and/or othersuitable optical device, and a handle portion. In at least oneembodiment, the optical device can be located on a first, or distal, endof the shaft and the handle portion can be located on a second, orproximal, end of the shaft. In various embodiments, the endoscope mayalso be configured to assist a surgeon in taking biopsies, retrievingforeign objects, and introducing surgical instruments into the surgicalsite.

Laparoscopic surgery is another minimally invasive surgical techniquewhere procedures in the abdominal or pelvic cavities can be performedthrough small incisions in the patient's body. A key element oflaparoscopic surgery is the use of a laparoscope which typicallyincludes a telescopic lens system that can be connected to a videocamera. In various embodiments, a laparoscope can further include afiber optic system connected to a halogen or xenon light source, forexample, in order to illuminate the surgical site. In variouslaparoscopic, and/or endoscopic, surgical procedures, a body cavity of apatient, such as the abdominal cavity, for example, can be insufflatedwith carbon dioxide gas, for example, in order to create a temporaryworking space for the surgeon. In such procedures, a cavity wall can beelevated above the organs within the cavity by the carbon dioxide gas.Carbon dioxide gas is usually used for insufflation because it can beeasily absorbed and removed by the body.

In at least one minimally invasive surgical procedure, an endoscopeand/or laparoscope can be inserted through a natural opening of apatient to allow a surgeon to access a surgical site. Such proceduresare generally referred to as Nature Orifice Transluminal EndoscopicSurgery or (NOTES)™ and can be utilized to treat tissue while reducingthe number of incisions, and external scars, to a patient's body. Invarious NOTES™ procedures, for example, an endoscope can include atleast one working channel defined therein, which can be used to allowthe surgeon to insert a surgical instrument therethrough in order toaccess the surgical site.

Minimally invasive surgical procedures may employ electrical ablationtherapy for the treatment of undesirable tissue such as diseased tissue,cancer, malignant and benign tumors, masses, lesions, and other abnormaltissue growths in a tissue treatment region. While conventionalapparatuses, systems, and methods for the electrical ablation ofundesirable tissue are effective, one drawback with conventionalelectrical ablation treatment is the resulting permanent damage that mayoccur to the healthy tissue surrounding the abnormal tissue dueprimarily to the detrimental thermal effects resulting from exposing thetissue to thermal energy generated by the electrical ablation device.This may be particularly true when exposing the tissue to electricpotentials sufficient to cause cell necrosis using high temperaturethermal therapies including focused ultrasound ablation, radiofrequency(RF) ablation, or interstitial laser coagulation. Other techniques fortissue ablation include chemical ablation, in which chemical agents areinjected into the undesirable tissue to cause ablation as well assurgical excision, cryotherapy, radiation, photodynamic therapy, Moh'smicrographic surgery, topical treatments with 5-fluorouracil, and/orlaser ablation. Other drawbacks of conventional thermal, chemical, andother ablation therapy are cost, length of recovery, and the paininflicted on the patient.

Conventional thermal, chemical, and other ablation techniques have beenemployed for the treatment of a variety of undesirable tissue. Thermaland chemical ablation techniques have been used for the treatment ofvaricose veins resulting from reflux disease of the greater saphenousvein (GSV), in which the varicose vein is stripped and then is exposedto either chemical or thermal ablation. Other techniques for thetreatment of undesirable tissue are more radical. Prostate cancer, forexample, may be removed using a prostatectomy, in which the entire orpart of prostate gland and surrounding lymph nodes are surgicallyremoved. Like most other forms of cancer, radiation therapy may be usedin conjunction with or as an alternate method for the treatment ofprostate cancer. Another thermal ablation technique for the treatment ofprostate cancer is RF interstitial tumor ablation (RITA) viatrans-rectal ultrasound guidance. While these conventional methods forthe treatment of prostate cancer are effective, they are not preferredby many surgeons and may result in detrimental thermal effects tohealthy tissue surrounding the prostate. Similar thermal ablationtechniques may be used for the treatment of basal cell carcinoma (BCC)tissue, a slowly growing cutaneous malignancy derived from the rapidlyproliferating basal layer of the epidermis. BCC tissue in tumors rangingin size from about 5 mm to about 40 mm may be thermally ablated with apulsed carbon dioxide laser. Nevertheless, carbon dioxide laser ablationis a thermal treatment method and may cause permanent damage to healthytissue surrounding the BCC tissue. Furthermore, this technique requirescostly capital investment in carbon dioxide laser equipment.

Undesirable tissue growing inside a body lumen such as the esophagus,large bowel, or in cavities formed in solid tissue such as the breast,for example, can be difficult to destroy using conventional ablationtechniques. Surgical removal of undesirable tissue, such as a malignantor benign tumor, from the breast is likely to leave a cavity. Surgicalresection of residual intralumenal tissue may remove only a portion ofthe undesirable tissue cells within a certain margin of healthy tissue.Accordingly, some undesirable tissue is likely to remain within the wallof the cavity due to the limitation of conventional ablation instrumentconfigurations, which may be effective for treating line-of-sightregions of tissue, but may be less effective for treating the residualundesirable tissue.

Accordingly, there remains a need for improved electrical ablationapparatuses, systems, and methods for the treatment of undesirabletissue found in diseased tissue, cancer, malignant and benign tumors,masses, lesions, and other abnormal tissue growths. There remains a needfor minimally invasive treatment of undesirable tissue through the useof irreversible electroporation (IRE) ablation techniques withoutcausing the detrimental thermal effects of conventional thermal ablationtechniques.

The foregoing discussion is intended only to illustrate various aspectsof the related art in the field of the invention at the time, and shouldnot be taken as a disavowal of claim scope.

SUMMARY

An aspect of the present disclosure is directed to an apparatus fortreating tissue in a tissue treatment region. The apparatus comprises anelectrode ring comprising an interior perimeter and an electrode probecomprising a proximal end and a distal end. The distal end of theelectrode probe is structured to axially translate relative to theinterior perimeter of the electrode ring. The electrode ring and theelectrode probe are operably structured to conduct current therebetweenwhen at least one of the electrode ring and the electrode probe isenergized by an energy source. Further, the energy source can be a RadioFrequency (RF) energy source, a pulsed energy source, an irreversibleelectroporation energy source, or a pulsed irreversible electroporationenergy source.

An aspect of the present disclosure is related to an electrical ablationsystem comprising an energy source, a housing that comprises a workingchannel and a rim, and a probe moveably positioned through the workingchannel of the housing. The probe comprises a distal portion that isstructured to move relative to the rim. Furthermore, the distal portionof the probe and the rim of the housing are operably structured toconduct current therebetween when at least one of the probe and the rimis energized by an energy source.

An aspect of the present disclosure is related to a method comprisingthe steps of obtaining an apparatus that comprises an electrode ring andan electrode probe. The electrode ring comprises an interior perimeterand a contact surface. The electrode probe comprises a proximal end anda distal end that is structured to axially translate relative to theinterior perimeter of the electrode ring. The electrode ring and theelectrode probe can be operably structured to conduct currenttherebetween when at least one of the electrode ring and the electrodeprobe is energized by an energy source. Further, the method can comprisethe steps of positioning the contact surface of the electrode ringagainst tissue, moving the distal end of the electrode probe axiallyrelative to the electrode ring, energizing at least one of the electrodering and the electrode probe to conduct current therebetween, and/orapplying a suctioning force to draw tissue into the electrode ring.

FIGURES

The novel features of the various described embodiments are set forthwith particularity in the appended claims. The various embodiments,however, both as to organization and methods of operation, together withadvantages thereof, may be understood in accordance with the followingdescription taken in conjunction with the accompanying drawings asfollows.

FIG. 1 is a schematic of an electrical ablation system and a flexibleendoscope according to various embodiments of the present disclosure;

FIG. 2 is a schematic illustrating one embodiment of the electricalablation device of the electrical ablation system of FIG. 1 treatingtissue in a tissue treatment region;

FIG. 3 is a schematic illustrating one embodiment of the electricalablation device of FIG. 2 treating tissue in a tissue treatment region;

FIG. 4 is a perspective view of an electrical ablation device accordingto various embodiments of the present disclosure;

FIG. 5 is a perspective view of one embodiment of the electricalablation device of FIG. 4 illustrating the cap of the device astransparent;

FIG. 6 is an elevational view of one embodiment of the electricalablation device of FIG. 4;

FIG. 7 is an elevational view of one embodiment of the electricalablation device of FIG. 4 with the cap and the attachment member removedtherefrom;

FIG. 8 is an elevational view of one embodiment of the electricalablation device of FIG. 4;

FIG. 9 is an elevational, cross-sectional view of one embodiment of theelectrical ablation device of FIG. 4;

FIG. 10 is an elevational view of one embodiment of the electricalablation device of FIG. 4 with the cap and the attachment member removedtherefrom;

FIG. 11 is an elevational view of one embodiment of the electrode probeof the electrical ablation device of FIG. 4 having a needle tip and atemperature sensor;

FIG. 12 is a side view of an electrode probe having a blunt tipaccording to various embodiments of the present disclosure;

FIG. 13 is an elevational view of an electrode probe having a hooked tipaccording to various embodiments of the present disclosure;

FIG. 14 is an elevational view of an electrode probe having a pull cableaccording to various embodiments of the present disclosure;

FIG. 15 is a perspective, cross-sectional view of one embodiment of theattachment member of the electrical ablation device of FIG. 4;

FIG. 16 is an elevational, cross-sectional view illustrating engagementof the attachment member and the cap of one embodiment of the electricalablation device of FIG. 4;

FIG. 17 is a perspective view of the cap of one embodiment of theelectrical ablation device of FIG. 4;

FIG. 18 is an elevational view of the cap of one embodiment of theelectrical ablation device of FIG. 4;

FIG. 19 is an elevational view of the cap of one embodiment of theelectrical ablation device of FIG. 4;

FIG. 20 is a plan view of the cap of one embodiment of the electricalablation device of FIG. 4;

FIG. 21 is a perspective view of the electrode ring of one embodiment ofthe electrical ablation device of FIG. 4 showing a plurality oftemperature sensors around the perimeter;

FIG. 22 is a perspective view of the second conductor, second conductorextension, and electrode ring of one embodiment of the electricalablation device of FIG. 4;

FIG. 23 is a schematic of one embodiment of the electrical ablationdevice of FIG. 4 illustrating a substantially conical necrotic zone; and

FIG. 24 is a schematic of one embodiment of the electrical ablationdevice of FIG. 4 illustrating a substantially conical necrotic zone.

DESCRIPTION

Various embodiments are directed to apparatuses, systems, and methodsfor the electrical ablation treatment of undesirable tissue such asdiseased tissue, cancer, malignant and benign tumors, masses, lesions,and other abnormal tissue growths. Numerous specific details are setforth to provide a thorough understanding of the overall structure,function, manufacture, and use of the embodiments as described in thespecification and illustrated in the accompanying drawings. It will beunderstood by those skilled in the art, however, that the embodimentsmay be practiced without such specific details. In other instances,well-known operations, components, and elements have not been describedin detail so as not to obscure the embodiments described in thespecification. Further, the embodiments described and illustrated hereinare non-limiting examples, and thus it can be appreciated that thespecific structural and functional details disclosed herein may berepresentative and do not necessarily limit the scope of theembodiments, the scope of which is defined solely by the appendedclaims.

Reference throughout the specification to “various embodiments,” “someembodiments,” “one embodiment,” or “an embodiment”, or the like, meansthat a particular feature, structure, or characteristic described inconnection with the embodiment is included in at least one embodiment.Thus, appearances of the phrases “in various embodiments,” “in someembodiments,” “in one embodiment,” or “in an embodiment”, or the like,in places throughout the specification are not necessarily all referringto the same embodiment. Furthermore, the particular features,structures, or characteristics may be combined in any suitable manner inone or more embodiments. Thus, the particular features, structures, orcharacteristics illustrated or described in connection with oneembodiment may be combined, in whole or in part, with the featuresstructures, or characteristics of one or more other embodiments withoutlimitation.

It will be appreciated that the terms “proximal” and “distal” may beused throughout the specification with reference to a clinicianmanipulating one end of an instrument used to treat a patient. The term“proximal” refers to the portion of the instrument closest to theclinician and the term “distal” refers to the portion located furthestfrom the clinician. It will be further appreciated that for concisenessand clarity, spatial terms such as “vertical,” “horizontal,” “up,” and“down” may be used herein with respect to the illustrated embodiments.However, surgical instruments may be used in many orientations andpositions, and these terms are not intended to be limiting and absolute.

Electrical ablation devices in accordance with the described embodimentsmay comprise one or more electrodes configured to be positioned into orproximal to undesirable tissue in a tissue treatment region (e.g.,target site, worksite) where there is evidence of abnormal tissuegrowth, for example. In general, the electrodes comprise an electricallyconductive portion (e.g., medical grade stainless steel) and areconfigured to electrically couple to an energy source. Once theelectrodes are positioned into or proximal to the undesirable tissue, anenergizing potential is applied to the electrodes to create an electricfield to which the undesirable tissue is exposed. The energizingpotential (and the resulting electric field) may be characterized bymultiple parameters such as frequency, amplitude, pulse width (durationof a pulse or pulse length), and/or polarity. Depending on thediagnostic or therapeutic treatment to be rendered, a particularelectrode may be configured either as an anode (+) or a cathode (−) ormay comprise a plurality of electrodes with at least one configured asan anode and at least one other configured as a cathode. Regardless ofthe initial polar configuration, the polarity of the electrodes may bereversed by reversing the polarity of the output of the energy source.

In various embodiments, a suitable energy source may comprise anelectrical waveform generator, which may be configured to create anelectric field that is suitable to create irreversible electroporationin undesirable tissue at various electric field amplitudes anddurations. The energy source may be configured to deliver irreversibleelectroporation pulses in the form of direct-current (DC) and/oralternating-current (AC) voltage potentials (e.g., time-varying voltagepotentials) to the electrodes. The irreversible electroporation pulsesmay be characterized by various parameters such as frequency, amplitude,pulse length, and/or polarity. The undesirable tissue may be ablated byexposure to the electric potential difference across the electrodes.

In one embodiment, the energy source may comprise a wireless transmitterto deliver energy to the electrodes using wireless energy transfertechniques via one or more remotely positioned antennas. Wireless energytransfer or wireless power transmission is the process of transmittingelectrical energy from an energy source to an electrical load withoutinterconnecting wires. An electrical transformer is the simplestinstance of wireless energy transfer. The primary and secondary circuitsof a transformer are not directly connected and the transfer of energytakes place by electromagnetic coupling through a process known asmutual induction. Power also may be transferred wirelessly using RFenergy. Wireless power transfer technology using RF energy is producedby Powercast, Inc. and can achieve an output of 6 volts for a littleover one meter. Other low-power wireless power technology has beenproposed such as described in U.S. Pat. No. 6,967,462, the entiredisclosure of which is incorporated by reference herein.

The apparatuses, systems, and methods in accordance with certaindescribed embodiments may be configured for minimally invasive ablationtreatment of undesirable tissue through the use of irreversibleelectroporation to be able to ablate undesirable tissue in a controlledand focused manner without inducing thermally damaging effects to thesurrounding healthy tissue. The apparatuses, systems, and methods inaccordance with the described embodiments may be configured to ablateundesirable tissue through the use of electroporation orelectropermeabilization. More specifically, in various embodiments, theapparatuses, systems, and methods in accordance with the describedembodiments may be configured to ablate undesirable tissue through theuse of irreversible electroporation. Electroporation increases thepermeabilization of a cell membrane by exposing the cell to electricpulses. The external electric field (electric potential/per unit length)to which the cell membrane is exposed to significantly increases theelectrical conductivity and permeability of the plasma in the cellmembrane. The primary parameter affecting the transmembrane potential isthe potential difference across the cell membrane. Irreversibleelectroporation is the application of an electric field of a specificmagnitude and duration to a cell membrane such that the permeabilizationof the cell membrane cannot be reversed, leading to cell death withoutinducing a significant amount of heat in the cell membrane. Thedestabilizing potential forms pores in the cell membrane when thepotential across the cell membrane exceeds its dielectric strengthcausing the cell to die under a process known as apoptosis and/ornecrosis. The application of irreversible electroporation pulses tocells is an effective way to ablate large volumes of undesirable tissuewithout deleterious thermal effects to the surrounding healthy tissueassociated with thermal-inducing ablation treatments. This is becauseirreversible electroporation destroys cells without heat and thus doesnot destroy the cellular support structure or regional vasculature. Adestabilizing irreversible electroporation pulse, suitable to cause celldeath without inducing a significant amount of thermal damage to thesurrounding healthy tissue, may have amplitude in the range of aboutseveral hundred to about several thousand volts and is generally appliedacross biological membranes over a distance of about severalmillimeters, for example, for a relatively long duration. Thus, theundesirable tissue may be ablated in-vivo through the delivery ofdestabilizing electric fields by quickly creating cell necrosis.

The apparatuses, systems, and methods for electrical ablation therapy inaccordance with the described embodiments may be adapted for use inminimally invasive surgical procedures to access the tissue treatmentregion in various anatomic locations such as the brain, lungs, breast,liver, gall bladder, pancreas, prostate gland, and various internal bodylumen defined by the esophagus, stomach, intestine, colon, arteries,veins, anus, vagina, cervix, fallopian tubes, and the peritoneal cavity,for example, without limitation. Minimally invasive electrical ablationdevices may be introduced to the tissue treatment region using a trocarinserted though a small opening formed in the patient's body or througha natural body orifice such as the mouth, anus, or vagina usingtranslumenal access techniques known as Natural Orifice TranslumenalEndoscopic Surgery (NOTES)™. Once the electrical ablation devices (e.g.,electrodes) are located into or proximal to the undesirable tissue inthe treatment region, electric field potentials can be applied to theundesirable tissue by the energy source. The electrical ablation devicescan comprise portions that may be inserted into the tissue treatmentregion percutaneously (e.g., where access to inner organs or othertissue is done via needle-puncture of the skin). Other portions of theelectrical ablation devices may be introduced into the tissue treatmentregion endoscopically (e.g., laparoscopically and/or thoracoscopically)through trocars or working channels of the endoscope, through smallincisions, or transcutaneously (e.g., where electric pulses aredelivered to the tissue treatment region through the skin).

FIG. 1 illustrates one embodiment of an electrical ablation system 10.The electrical ablation system 10 may be employed to ablate undesirabletissue such as diseased tissues, cancers, tumors, masses, lesions,abnormal tissue growths inside a patient using electrical energy. Theelectrical ablation system 10 may be used in conjunction withendoscopic, laparoscopic, thoracoscopic, open surgical procedures viasmall incisions or keyholes, percutaneous techniques, transcutaneoustechniques, and/or external non-invasive techniques, or any combinationsthereof without limitation. The electrical ablation system 10 may beconfigured to be positioned within a natural body orifice of the patientsuch as the mouth, anus, or vagina and advanced through internal bodylumen or cavities such as the esophagus, colon, cervix, urethra, forexample, to reach the tissue treatment region. The electrical ablationsystem 10 also may be configured to be positioned and passed through asmall incision or keyhole formed through the skin or abdominal wall ofthe patient to reach the tissue treatment region using a trocar. Thetissue treatment region may be located in the brain, lungs, breast,liver, gall bladder, pancreas, prostate gland, various internal bodylumen defined by the esophagus, stomach, intestine, colon, arteries,veins, anus, vagina, cervix, fallopian tubes, and the peritoneal cavity,for example, without limitation. The electrical ablation system 10 canbe configured to treat a number of lesions and ostepathologiescomprising metastatic lesions, tumors, fractures, infected sites, and/orinflamed sites. Once positioned into or proximate the tissue treatmentregion, the electrical ablation system 10 can be actuated (e.g.,energized) to ablate the undesirable tissue. In one embodiment, theelectrical ablation system 10 may be configured to treat diseased tissuein the gastrointestinal (GI) tract, esophagus, lung, or stomach that maybe accessed orally. In another embodiment, the electrical ablationsystem 10 may be adapted to treat undesirable tissue in the liver orother organs that may be accessible using translumenal access techniquessuch as, without limitation, NOTES™ techniques, where the electricalablation devices may be initially introduced through a natural orificesuch as the mouth, anus, or vagina and then advanced to the tissuetreatment site by puncturing the walls of internal body lumen such asthe stomach, intestines, colon, cervix. In various embodiments, theelectrical ablation system 10 may be adapted to treat undesirable tissuein the brain, liver, breast, gall bladder, pancreas, or prostate gland,using one or more electrodes positioned percutaneously,transcutaneously, translumenally, minimally invasively, and/or throughopen surgical techniques, or any combination thereof.

In one embodiment, the electrical ablation system 10 may be employed inconjunction with a flexible endoscope 12, as well as a rigid endoscope,laparoscope, or thoracoscope, such as the GIF-H180 model available fromOlympus Corporation. In one embodiment, the endoscope 12 may beintroduced to the tissue treatment region trans-anally through thecolon, trans-orally through the esophagus and stomach, trans-vaginallythrough the cervix, transcutaneously, or via an external incision orkeyhole formed in the abdomen in conjunction with a trocar. Theelectrical ablation system 10 may be inserted and guided into orproximate the tissue treatment region using the endoscope 12.

In the embodiment illustrated in FIG. 1, the endoscope 12 comprises anendoscope handle 34 and an elongate relatively flexible shaft 32. Thedistal end of the flexible shaft 32 may comprise a light source and aviewing port. Optionally, the flexible shaft 32 may define one or moreworking channels for receiving various instruments, such as electricalablation devices, for example, therethrough. Images within the field ofview of the viewing port are received by an optical device, such as acamera comprising a charge coupled device (CCD) usually located withinthe endoscope 12, and are transmitted to a display monitor (not shown)outside the patient.

In one embodiment, the electrical ablation system 10 may comprise anelectrical ablation device 20, a plurality of electrical conductors 18,a handpiece 16 comprising an activation switch 62, and an energy source14, such as an electrical waveform generator, electrically coupled tothe activation switch 62 and the electrical ablation device 20. Theelectrical ablation device 20 comprises a relatively flexible member orshaft 22 that may be introduced to the tissue treatment region using avariety of known techniques such as an open incision and a trocar,through one of more of the working channels of the endoscope 12,percutaneously, or transcutaneously, for example.

In one embodiment, one or more electrodes (e.g., needle electrodes,balloon electrodes), such as first and second electrodes 24 a,b, extendout from the distal end of the electrical ablation device 20. In oneembodiment, the first electrode 24 a may be configured as the positiveelectrode and the second electrode 24 b may be configured as thenegative electrode. The first electrode 24 a is electrically connectedto a first electrical conductor 18 a, or similar electrically conductivelead or wire, which is coupled to the positive terminal of the energysource 14 through the activation switch 62. The second electrode 24 b iselectrically connected to a second electrical conductor 18 b, or similarelectrically conductive lead or wire, which is coupled to the negativeterminal of the energy source 14 through the activation switch 62. Theelectrical conductors 18 a,b are electrically insulated from each otherand surrounding structures, except for the electrical connections to therespective electrodes 24 a,b. In various embodiments, the electricalablation device 20 may be configured to be introduced into or proximatethe tissue treatment region using the endoscope 12 (laparoscope orthoracoscope), open surgical procedures, or external and non-invasivemedical procedures. The electrodes 24 a,b may be referred to herein asendoscopic or laparoscopic electrodes, although variations thereof maybe inserted transcutaneously or percutaneously. As discussed herein,either one or both electrodes 24 a,b may be adapted and configured toslideably move in and out of a cannula, lumen, or channel defined withinthe flexible shaft 22.

Once the electrodes 24 a,b are positioned at the desired location intoor proximate the tissue treatment region, the electrodes 24 a,b may beconnected to or disconnected from the energy source 14 by actuating orde-actuating the switch 62 on the handpiece 16. The switch 62 may beoperated manually or may be mounted on a foot switch (not shown), forexample. The electrodes 24 a,b deliver electric field pulses to theundesirable tissue. The electric field pulses may be characterized basedon various parameters such as pulse shape, amplitude, frequency, andduration. The electric field pulses may be sufficient to induceirreversible electroporation in the undesirable tissue. The inducedpotential depends on a variety of conditions such as tissue type, cellsize, and electrical pulse parameters. The primary electrical pulseparameter affecting the transmembrane potential for a specific tissuetype is the amplitude of the electric field and pulse length that thetissue is exposed to.

In one embodiment, a protective sleeve or sheath 26 may be slideablydisposed over the flexible shaft 22 and within a handle 28. In anotherembodiment, the sheath 26 may be slideably disposed within the flexibleshaft 22 and the handle 28, without limitation. The sheath 26 isslideable and may be located over the electrodes 24 a,b to protect thetrocar and prevent accidental piercing when the electrical ablationdevice 20 is advanced therethrough. Either one or both of the electrodes24 a,b of the electrical ablation device 20 may be adapted andconfigured to slideably move in and out of a cannula, lumen, or channelformed within the flexible shaft 22. As described in greater detailherein, the second electrode 24 b may be fixed in place. The secondelectrode 24 b may provide a pivot about which the first electrode 24 acan be moved in an arc to other points in the tissue treatment region totreat larger portions of the diseased tissue that cannot be treated byfixing the electrodes 24 a,b in one location. In one embodiment, eitherone or both of the electrodes 24 a,b may be adapted and configured toslideably move in and out of a working channel formed within a flexibleshaft 32 of the flexible endoscope 12 or may be located independently ofthe flexible endoscope 12.

In one embodiment, the first and second electrical conductors 18 a,b maybe provided through the handle 28. In the illustrated embodiment, thefirst electrode 24 a can be slideably moved in and out of the distal endof the flexible shaft 22 using a slide member 30 to retract and/oradvance the first electrode 24 a. In various embodiments either or bothelectrodes 24 a,b may be coupled to the slide member 30, or additionalslide members, to advance and retract the electrodes 24 a,b, e.g.,position the electrodes 24 a,b. In the illustrated embodiment, the firstelectrical conductor 18 a coupled to the first electrode 24 a is coupledto the slide member 30. In this manner, the first electrode 24 a, whichis slideably movable within the cannula, lumen, or channel defined bythe flexible shaft 22, can advanced and retracted with the slide member30.

In various other embodiments, transducers or sensors 29 may be locatedin the handle 28 of the electrical ablation device 20 to sense the forcewith which the electrodes 24 a,b penetrate the tissue in the tissuetreatment zone. This feedback information may be useful to determinewhether either one or both of the electrodes 24 a,b have been properlyinserted in the tissue treatment region. As is particularly well known,cancerous tumor tissue tends to be denser than healthy tissue and thusgreater force is required to insert the electrodes 24 a,b therein. Thetransducers or sensors 29 can provide feedback to the operator, surgeon,or clinician to physically sense when the electrodes 24 a,b are placedwithin the cancerous tumor. The feedback information provided by thetransducers or sensors 29 may be processed and displayed by circuitslocated either internally or externally to the energy source 14. Thesensor 29 readings may be employed to determine whether the electrodes24 a,b have been properly located within the cancerous tumor therebyassuring that a suitable margin of error has been achieved in locatingthe electrodes 24 a,b.

In one embodiment, the input to the energy source 14 may be connected toa commercial power supply by way of a plug (not shown). The output ofthe energy source 14 is coupled to the electrodes 24 a,b, which may beenergized using the activation switch 62 on the handpiece 16, or in oneembodiment, an activation switch mounted on a foot activated pedal (notshown). The energy source 14 may be configured to produce electricalenergy suitable for electrical ablation, as described in more detailherein.

In one embodiment, the electrodes 24 a,b are adapted and configured toelectrically couple to the energy source 14 (e.g., generator, waveformgenerator). Once electrical energy is coupled to the electrodes 24 a,b,an electric field is formed at a distal end of the electrodes 24 a,b.The energy source 14 may be configured to generate electric pulses at apredetermined frequency, amplitude, pulse length, and/or polarity thatare suitable to induce irreversible electroporation to ablatesubstantial volumes of undesirable tissue in the treatment region. Forexample, the energy source 14 may be configured to deliver DC electricpulses having a predetermined frequency, amplitude, pulse length, and/orpolarity suitable to induce irreversible electroporation to ablatesubstantial volumes of undesirable tissue in the treatment region. TheDC pulses may be positive or negative relative to a particular referencepolarity. The polarity of the DC pulses may be reversed or inverted frompositive-to-negative or negative-to-positive a predetermined number oftimes to induce irreversible electroporation to ablate substantialvolumes of undesirable tissue in the treatment region.

In one embodiment, a timing circuit may be coupled to the output of theenergy source 14 to generate electric pulses. The timing circuit maycomprise one or more suitable switching elements to produce the electricpulses. For example, the energy source 14 may produce a series of nelectric pulses (where n is any positive integer) of sufficientamplitude and duration to induce irreversible electroporation suitablefor tissue ablation when the n electric pulses are applied to theelectrodes 24 a,b. In one embodiment, the electric pulses may have afixed or variable pulse length, amplitude, and/or frequency.

The electrical ablation device 20 may be operated either in bipolar ormonopolar mode. In bipolar mode, the first electrode 24 a iselectrically connected to a first polarity and the second electrode 24 bis electrically connected to the opposite polarity. For example, inmonopolar mode, the first electrode 24 a is coupled to a prescribedvoltage and the second electrode 24 b is set to ground. In theillustrated embodiment, the energy source 14 may be configured tooperate in either the bipolar or monopolar modes with the electricalablation system 10. In bipolar mode, the first electrode 24 a iselectrically connected to a prescribed voltage of one polarity and thesecond electrode 24 b is electrically connected to a prescribed voltageof the opposite polarity. When more than two electrodes are used, thepolarity of the electrodes may be alternated so that any two adjacentelectrodes may have either the same or opposite polarities, for example.

In one embodiment, the energy source 14 may be configured to produce RFwaveforms at predetermined frequencies, amplitudes, pulse widths ordurations, and/or polarities suitable for electrical ablation of cellsin the tissue treatment region. One example of a suitable RF energysource is a commercially available conventional, bipolar/monopolarelectrosurgical RF generator such as Model Number ICC 350, availablefrom Erbe, GmbH.

In one embodiment, the energy source 14 may be configured to producedestabilizing electrical potentials (e.g., fields) suitable to induceirreversible electroporation. The destabilizing electrical potentialsmay be in the form of bipolar/monopolar DC electric pulses suitable forinducing irreversible electroporation to ablate tissue undesirabletissue with the electrical ablation device 20. A commercially availableenergy source suitable for generating irreversible electroporationelectric filed pulses in bipolar or monopolar mode is a pulsed DCgenerator such as Model Number ECM 830, available from BTX MolecularDelivery Systems. In bipolar mode, the first electrode 24 a may beelectrically coupled to a first polarity and the second electrode 24 bmay be electrically coupled to a second (e.g., opposite) polarity of theenergy source 14. Bipolar/monopolar DC electric pulses may be producedat a variety of frequencies, amplitudes, pulse lengths, and/orpolarities. Unlike RF ablation systems, however, which require highpower and energy levels delivered into the tissue to heat and thermallydestroy the tissue, irreversible electroporation requires very littleenergy input into the tissue to kill the undesirable tissue without thedetrimental thermal effects because with irreversible electroporationthe cells are destroyed by electric field potentials rather than heat.

In one embodiment, the energy source 14 may be coupled to the first andsecond electrodes 24 a,b by either a wired or a wireless connection. Ina wired connection, the energy source 14 is coupled to the electrodes 24a,b by way of the electrical conductors 18 a,b, as shown. In a wirelessconnection, the electrical conductors 18 a,b may be replaced with afirst antenna (not shown) coupled the energy source 14 and a secondantenna (not shown) coupled to the electrodes 24 a,b, wherein the secondantenna is remotely located from the first antenna. In one embodiment,the energy source may comprise a wireless transmitter to deliver energyto the electrodes using wireless energy transfer techniques via one ormore remotely positioned antennas.

In at least one embodiment, the energy source 14 can be configured toproduce DC electric pulses at frequencies in the range of approximately1 Hz to approximately 10000 Hz, amplitudes in the range of approximately±100 to approximately ±8000 VDC, and pulse lengths (e.g., pulse width,pulse duration) in the range of approximately 1 μs to approximately 100ms. In at least one embodiment, the energy source can be configured toproduce biphasic waveforms and/or monophasic waveforms that alternatearound approximately 0V. In various embodiments, for example, thepolarity of the electric potentials coupled to the electrodes 24 a,b canbe reversed during the electrical ablation therapy. For example,initially, the DC electric pulses can have a positive polarity and anamplitude in the range of approximately +100 to approximately +3000 VDC.Subsequently, the polarity of the DC electric pulses can be reversedsuch that the amplitude is in the range of approximately −100 toapproximately −3000 VDC. In another embodiment, the DC electric pulsescan have an initial positive polarity and amplitude in the range ofapproximately +100 to +6000 VDC and a subsequently reversed polarity andamplitude in the range of approximately −100 to approximately −6000 VDC.

In at least one embodiment, the undesirable cells in the tissuetreatment region can be electrically ablated with DC pulses suitable toinduce irreversible electroporation at frequencies of approximately 10Hz to approximately 100 Hz, amplitudes in the range of approximately+700 to approximately +1500 VDC, and pulse lengths of approximately 10μs to approximately 50 μs. In another embodiment, the abnormal cells inthe tissue treatment region can be electrically ablated with anelectrical waveform having an amplitude of approximately +500 VDC andpulse duration of approximately 20 ms delivered at a pulse period T orrepetition rate, frequency f=1/T, of approximately 10 Hz. In anotherembodiment, the undesirable cells in the tissue treatment region can beelectrically ablated with DC pulses suitable to induce irreversibleelectroporation at frequencies of approximately 200 Hz, amplitudes inthe range of approximately +3000 VDC, and pulse lengths of approximately10 ms. It has been determined that an electric field strength of1,000V/cm can be suitable for destroying living tissue by inducingirreversible electroporation by DC electric pulses.

In various embodiments, the energy source 14 can be configured toproduce AC electric pulses at frequencies in the range of approximately1 Hz to approximately 10000 Hz, amplitudes in the range of approximately±8000 to approximately ±8000 VAC, and pulse lengths (e.g., pulse width,pulse duration) in the range of approximately 1 μs to approximately 100ms. In one embodiment, the undesirable cells in the tissue treatmentregion can be electrically ablated with AC pulses suitable to induceirreversible electroporation at pulse frequencies of approximately 4 Hz,amplitudes of approximately ±6000 VAC, and pulse lengths ofapproximately 20 ms. It has been determined that an electric fieldstrength of 1,500V/cm can be suitable for destroying living tissue byinducing irreversible electroporation by AC electric pulses.

Various electrical ablation devices are disclosed in commonly-owned U.S.patent application Ser. No. 11/897,676 titled “ELECTRICAL ABLATIONSURGICAL INSTRUMENTS,” filed Aug. 31, 2007, now U.S. Patent ApplicationPublication No. 2009/0062788, the entire disclosure of which isincorporated herein by reference in its entirety. Various other devicesare disclosed in commonly-owned U.S. patent application Ser. No.12/352,375, titled “ELECTRICAL ABLATION DEVICES”, filed on Jan. 12,2009, now U.S. Patent Application Publication No. 2010/0179530 theentire disclosure of which is incorporated herein by reference in itsentirety.

FIG. 2 illustrates one embodiment of the electrical ablation system 10shown in FIG. 1 in use to treat undesirable tissue 48 located in theliver 50. The undesirable tissue 48 may be representative of a varietyof diseased tissues, cancers, tumors, masses, lesions, abnormal tissuegrowths, for example. In use, the electrical ablation device 20 may beintroduced into or proximate the tissue treatment region through a port52 of a trocar 54. The trocar 54 is introduced into the patient via asmall incision 59 formed in the skin 56. The endoscope 12 may beintroduced into the patient trans-anally through the colon,trans-vaginally, trans-orally down the esophagus and through the stomachusing translumenal techniques, or through a small incision or keyholeformed through the patient's abdominal wall (e.g., the peritoneal wall).The endoscope 12 may be employed to guide and locate the distal end ofthe electrical ablation device 20 into or proximate the undesirabletissue 48. Prior to introducing the flexible shaft 22 through the trocar54, the sheath 26 is slid over the flexible shaft 22 in a directiontoward the distal end thereof to cover the electrodes 24 a,b until thedistal end of the electrical ablation device 20 reaches the undesirabletissue 48.

Once the electrical ablation device 20 has been suitably introduced intoor proximate the undesirable tissue 48, the sheath 26 is retracted toexpose the electrodes 24 a,b to treat the undesirable tissue 48. Toablate the undesirable tissue 48, the operator initially may locate thefirst electrode 24 a at a first position 58 a and the second electrode24 b at a second position 60 using endoscopic visualization andmaintaining the undesirable tissue 48 within the field of view of theflexible endoscope 12. The first position 58 a may be near a perimeteredge of the undesirable tissue 48. Once the electrodes 24 a,b arelocated into or proximate the undesirable tissue 48, the electrodes 24a,b are energized with irreversible electroporation pulses to create afirst necrotic zone 65 a. For example, once the first and secondelectrodes 24 a,b are located in the desired positions 60 and 58 a, theundesirable tissue 48 may be exposed to an electric field generated byenergizing the first and second electrodes 24 a,b with the energy source14. The electric field may have a magnitude, frequency, and pulse lengthsuitable to induce irreversible electroporation in the undesirabletissue 48 within the first necrotic zone 65 a. The size of the necroticzone is substantially dependent on the size and separation of theelectrodes 24 a,b, as previously discussed. The treatment time isdefined as the time that the electrodes 24 a,b are activated orenergized to generate the electric pulses suitable for inducingirreversible electroporation in the undesirable tissue 48.

This procedure may be repeated to destroy relatively larger portions ofthe undesirable tissue 48. The position 60 may be taken as a pivot pointabout which the first electrode 24 a may be rotated in an arc of radius“r,” the distance between the first and second electrodes 24 a,b. Priorto rotating about the second electrode 24 b, the first electrode 24 a isretracted by pulling on the slide member 30 in a direction toward theproximal end and rotating the electrical ablation device 20 about thepivot point formed at position 60 by the second electrode 24 b. Once thefirst electrode 24 a is rotated to a second position 58 b, it isadvanced to engage the undesirable tissue 48 at point 58 b by pushing onthe slide member 30 in a direction towards the distal end. A secondnecrotic zone 65 b is formed upon energizing the first and secondelectrodes 24 a,b. A third necrotic zone 65 c is formed by retractingthe first electrode 24 a, pivoting about pivot point 60 and rotating thefirst electrode 24 a to a new location in third position 58 c, advancingthe first electrode 24 a into the undesirable tissue 48 and energizingthe first and second electrodes 24 a,b. This process may be repeated asoften as necessary to create any number of necrotic zones 65 p, where pis any positive integer, within multiple circular areas of radius “r,”for example, that is suitable to ablate the entire undesirable tissue 48region. At anytime, the surgeon or clinician can reposition the firstand second electrodes 24 a,b and begin the process anew. Those skilledin the art will appreciate that similar techniques may be employed toablate any other undesirable tissues that may be accessible trans-anallythrough the colon, and/or orally through the esophagus and the stomachusing translumenal access techniques. Therefore, the embodiments are notlimited in this context.

FIG. 3 illustrates a detailed view of one embodiment of the electricalablation system 10 shown in FIG. 2 in use to treat undesirable tissue 48located in the liver 50. The first and second electrodes 24 a,b areembedded into or proximate the undesirable tissue 48 on the liver 50.The first and second electrodes 24 a,b are energized to deliver one ormore electrical pulses of amplitude and length sufficient to induceirreversible electroporation in the undesirable tissue 48 and create thefirst necrotic zone 65 a. Additional electric pulses may be applied tothe tissue immediately surrounding the respective electrodes 24 a,b toform second, thermal, necrotic zones 63 a,b near theelectrode-tissue-interface. The duration of an irreversibleelectroporation energy pulse determines whether the temperature of thetissue 63 a,b immediately surrounding the respective electrodes 24 a,braises to a level sufficient to create thermal necrosis. As previouslydiscussed, varying the electrode 24 a,b size and spacing can control thesize and shape of irreversible electroporation induced necrotic zone 65a. Electric pulse amplitude and length can be varied to control the sizeand shape of the thermally induced necrotic zones near thetissue-electrode-interface.

Referring now to FIGS. 4-22, in various embodiments, an electricalablation device 120 can comprise a first electrode 124 and a secondelectrode 125. In various embodiments the first electrode 124 cancomprise of an electrode probe, for example, and the second electrode125 can comprise of an electrode ring, for example. As described ingreater detail herein, the electrode probe 124 can be configured to moveaxially relative to the electrode ring 125, for example. In variousembodiments, the electrical ablation device 120 can comprise a pluralityof electrode probes 124 and/or a plurality of electrode rings 125.Similar to the electrodes 24 a and 24 b, described in greater detailherein, the first electrode 124 and the second electrode 125 can bestructured to conduct current therebetween when at least one of theelectrodes 124, 125 is energized by an energy source 14 (FIG. 1).Furthermore, the energy source 14 (FIG. 1) that is coupled to at leastone of the first and/or second electrodes 124, 125 can comprise a radiofrequency (RF) energy source, a pulsed energy source, an irreversibleelectroporation energy source and/or a pulsed electroporation energysource, for example. Furthermore, as described in greater detail herein,the pulse length, amplitude, and/or frequency can be selected tonon-thermally ablate tissue. Also, the energy source 14 (FIG. 1) can beconfigured to produce direct and/or alternating current resulting inbiphasic and/or monophasic waveforms, as described in greater detailhere.

In various embodiments the electrical ablation device 120 can comprise aflexible shaft 122, an attachment member 160 and/or a cap 140. Asdescribed in greater detail herein, the attachment number 160 can becoupled to the flexible shaft 122 at or near the distal end 192 thereof.Furthermore, in some embodiments, the cap 140 can releasably engage theattachment member 160. In various embodiments, a bore 190 may extendthrough the attachment portion 160 and/or through the cap 140 and atleast a portion of the flexible shaft 122 can be positioned in the bore190, for example. In some embodiments, at least a portion of theelectrode probe 124 can be axially positioned through at least a portionof the flexible shaft 122, the attachment member 160 and/or the cap 140,for example. Furthermore, the electrode probe 124 can comprise a firstconductor 118 extending therefrom, for example. In various embodiments,at least a portion of the electrode probe 124 and/or first conductor 118can be configured to move within at least one of the flexible shaft 122,the attachment member 160 and/or the cap 140, for example. In variousembodiments, the first conductor 118 can be configured to slide,translate, rotate, or a combination thereof within the flexible shaft122. For example, the first conductor 118 can be configured to translatewithin the flexible shaft 122, the attachment member 160 and the cap140. Similar to the slide member 30 (FIG. 1) described in greater detailhere, a slide member can operably move the electrode probe 124. Invarious embodiments, the slide member can be coupled to the firstconductor 118. In such embodiments, the electrode probe 124 can beslideably moved in and out of the distal end of the flexible shaft 122using the slide member to retract and/or advance the first conductor118, for example.

In various embodiments, the electrical ablation device 120 can comprisea plurality of electrode probes 124. The electrode probes can beconfigured to move within the flexible shaft 122, attachment member 160and/or the cap 140, for example. The electrode probes can move togetherand/or independently, for example. Furthermore, each electrode probe cancomprise a conductor, for example. Alternatively or additionally, atleast two electrode probes can extend from a single conductor, forexample.

Referring now primarily to the embodiment illustrated in FIG. 11, thefirst electrode or electrode probe 124 can comprise a distal end 170. Invarious embodiments, a needle tip 172 can be positioned at or near thedistal end 170 of the electrode probe 124. In various embodiments, theelectrode probe 124 can also comprise at least one temperature sensor174. The temperature sensor can be positioned at or near the distal end170 of the electrode probe 124, for example. In various embodiments, thetemperature sensor 174 can measure the temperature of tissue 63 a (FIG.3) immediately surrounding the electrode probe 124, for example. Thesensor 174 can communicate the measurement to transducers and/orcircuits located either internally or externally to the flexibleendoscope 12 and/or the energy source 14 (FIG. 1). The sensor 174 canprovide feedback to the operator, surgeon, or clinician such that theoperator, surgeon, or clinician can adjust the power level of the energysource 14 (FIG. 1) to prevent thermal ablation of the tissue 63 aimmediately surrounding the electrode probe 124. In other embodiments,the sensor 174 can provide feedback to the operator, surgeon, orclinician such that the operator, surgeon or clinician can adjust thepower level to thermally ablate tissue 63 a immediately surrounding theelectrode probe 124. As described in greater detail herein, theelectrode ring 125 can also comprise at least one temperature sensor 158such that a temperature gradient across the tissue treatment region canbe determined and communicated to the operator, surgeon or clinician.

Referring now to the embodiment illustrated in FIG. 12, in variousembodiments a second electrode probe 224 can comprise a substantiallyflat or blunt distal end 270. In other embodiments, referring now to theembodiment illustrated in FIG. 13, an electrode probe 324 can comprise ahooked tip 326, for example. In various embodiments, the hooked tip 326can be inserted into tissue in a tissue treatment region and thenretracted such that the tip 326 pulls and/or draws the tissue into thecap 140. Similar to the suction force described in greater detailherein, the amount of tissue drawn into the cap 140 by the hooked tip326 can affect the necrotic zone treated by the electrical ablationdevice 120. In other embodiments, referring now to the embodimentillustrated in FIG. 14, the distal end 470 of the electrode probe 424can comprise a pull string 474, for example. In various embodiments, thepull string 474 can be positioned at and/or near a needle tip 472 at thedistal end 470 of the electrode probe 424, for example. The draw pull474 can be looped around the electrode probe 424. In variousembodiments, the operator, surgeon or clinician can control the positionof the distal end 470 of the electrode probe 424 by manipulating thedraw string 474 such that the distal end 470 of the electrode probe 424moves, pivots, and/or bends relative to electrode ring 125 (FIG. 7), forexample.

Referring now primarily to the embodiment illustrated in FIGS. 5 and 9,the electrode probe 124 can be positioned relative to the flexible shaft122. In various embodiments, the flexible shaft 122 can comprise anelastic and/or resilient material such that the flexible shaft 122 canbend, twist, torque, and/or be otherwise manipulated by the operator,surgeon, or clinician during use, similar to flexible shaft 22 (FIGS. 1and 2) described in greater detail herein. In some embodiments, at leasta portion of the electrode probe 124 can be positioned within a bore 136that extends through the flexible shaft 122 from a proximal end 191 to adistal end 192 thereof. In various embodiments, the flexible shaft 122can comprise a top surface 137 at the distal end 192 having an opening138 therein. The bore 136 can extend through the flexible shaft 122 tothe opening 138 in the top surface 137, for example. As described ingreater detail herein, the first conductor 118 can extend from the firstelectrode 124. In various embodiments, the first conductor 118 of theelectrode probe 124 can extend through the bore 136. In variousembodiments, an inner surface of the bore 136 can comprise an insulatedmaterial such that the electrode probe 124 and/or first conductor 118 iselectrically insulated from the flexible shaft 122 and/or the electricalablation device 120, for example. For example, an insulating coating cancover the inner surface of the bore 136 along the length of the flexibleshaft 122. Additionally or alternatively, the first conductor 118 cancomprise an insulated material such that the electrode probe 124 and/orfirst conductor 118 is electrically insulated from the flexible shaft122 and/or the electrical ablation device 120, for example. For example,an insulating coating can cover the outer surface of the secondconductor 118 along the length thereof.

In various embodiments, the electrical ablation device 120 can comprisean attachment member 160. Referring primarily to FIG. 9, the attachmentmember 160 can be coupled to the flexible shaft 122. In variousembodiments, the attachment member 160 can be fixedly attached to theflexible shaft 122. The attachment member 160 can be attached to theflexible shaft 122 by an adhesive and/or by threads (not shown) in theflexible shaft 122 and attachment member 160, for example. In someembodiments, the attachment member 160 can be an integral component ofthe flexible shaft 122, for example, such that the flexible shaft 122and attachment member 160 comprise a single, integrated piece.

Referring now to the embodiment illustrated in FIGS. 15 and 16, theattachment member 160 can comprise a body 162 and an inner surface 163.In various embodiments, the attachment member 160 can also comprise anattachment portion 164. The attachment portion 164 can comprise at leastone connective ridge 166, for example. In various embodiments, theattachment portion 164 can comprise a plurality of connective ridges166. The connective ridge 166 can extend from the body 162 of theattachment member 160 and into the bore 190 defined by the body 162 ofthe attachment member 160. In various embodiments, the connective ridge166 can comprise an annular or semi-annular projection from the innersurface 163 of the attachment member 160. In various embodiments, theconnective ridge 163 can comprise a plurality of projections from theinner surface 163 of the attachment member. In such embodiments, gaps(not shown) can be positioned intermediate the projections, for example.

In some embodiments, the connective ridge 166 can comprise a flat edge165 and/or a contoured edge 167. As described in greater detail herein,the flat edge 165 and/or contoured edge 167 of the connective ridge 166can be configured to engage an element on the cap 140 such that theconnective member 160 is attached to the cap 140. In some embodiments,the attachment member 160 can be fixedly attached the cap 140. In otherembodiment, the attachment member 160 can be removably attached to thecap 140 such as, for example, by a detent assembly, a plurality ofspring-loaded pins, a resilient projection extending from the body 162of the attachment member 160 and/or threads, for example, on the innersurface 163 of the body 162 that are configured to threadably engagecorresponding threads in the cap 140. In various embodiments, theattachment member 160 can also comprise a channel 168, which isconfigured to receive at least a portion of the second conductor 119and/or second conductor extension 180, as described in greater detailherein.

Referring now to FIGS. 16-20, the cap 140 of the electrical ablationdevice 120 can comprise a body portion 142. In various embodiments, thebody portion 142 can comprise a substantially cylindrical shape. Inother embodiments, the body 142 can comprise a circular, ellipticaland/or polygonal cross-section, for example. Furthermore, in someembodiments, the cap 140 may not form a completely closed loop or shape,but can comprise a gap, for example. In various embodiments, the cap 140can comprise a rim 144. In some embodiments, the rim 144 can bepositioned at the distal end of the body 142 of the cap 140.

In various embodiments, referring still to FIGS. 16-20, an attachmentportion 147 can be positioned at a proximal end or portion of the cap140. The attachment portion 147 can releasably secure the cap 140 to theattachment portion 164 of the attachment member 160, as described ingreater detail herein. In various embodiments, the attachment portion147 of the cap 140 can fit within the attachment member 160, forexample. In other embodiments, the attachment portion 164 of theattachment member 160 can fit within the attachment portion 147 of thecap 140, for example. In various embodiments, the attachment portion 147can comprise a flange 148, for example. In some embodiments, the flange148 can comprise a smaller diameter than the diameter of the bodyportion 142 of the cap 140. The flange 148 can be configured to fitwithin the attachment portion 164 of the attachment member 160. In someembodiments, the flange 147 can comprise at least one depression 149that is configured to engage a connective ridge 166 in the attachmentportion 164 of the attachment member 160, for example. The depression149 in the flange 147 can receive the connective ridge 166, for example.In some embodiments, the connective ridge 166 can engage the depression149 of the flange 148 of the attachment portion 160 by a snap-fitengagement. In various embodiments, the attachment portion 147 cancomprise a plurality of depressions 149. For example, the attachmentportion 147 can comprise the same number of depressions as theattachment member 160 comprises number of connective ridges 166 suchthat each connective ridge 166 is configured to engage one depression149 in the attachment portion 147 of the cap 140.

Referring now primarily to the embodiment illustrated in FIGS. 18 and19, the cap 140 can comprise a rim 144. In various embodiments, portionsof the rim 144 can comprise a curved, angled, and/or flat surface(s),for example. In various embodiments, the rim 144 can slant across thediameter of the cap 140, for example, such that the rim 144 slantsrelative to a proximal portion of the cap 140. For example, the rim 144can be angularly positioned relative to flange 148 and/or depression 149in the attachment portion 147 of the cap 140. Referring primarily toFIG. 20, in various embodiments, the rim 144 of the cap 140 can comprisea step or contour 145. In various embodiments, as described in greaterdetail herein, the contour 145 can be configured to receive at least aportion of electrode ring 125, for example. In some embodiments, thecontour 145 can match or substantially match the bottom surface of theelectrode ring 125, as described in greater detail herein. In someembodiments, the cap 140 can also comprise a channel 143 that isconfigured to receive the second conductor 119 and/or the secondconductor extension 180, for example. Furthermore, the cap 140 cancomprise an inner surface 146 that defines the bore 190 through the cap140 and/or through the attachment portion 160, for example.

Referring now to the embodiment illustrated in FIG. 16, the cap 140 canbe configured to engage the attachment portion 160. In variousembodiments, the attachment portion 164 of the attachment member 160 canengage the attachment portion 147 of the cap 140, for example. As shownin FIG. 16, the connective ridge 166 of the attachment portion 164 ofthe attachment member 160 can engage the depression 149 in the flange148 of the attachment portion 147 of the cap 140. In variousembodiments, the outer surface of the flange 148 can be configured toabut the inner surface 163 of the attachment member 160, for example.Furthermore, when the attachment member 160 is removably attached to thecap 140, the channel 158 in the attachment member 160 can be alignedwith or substantially aligned with the channel 143 in the cap 140. Asdescribed in greater detail herein, the channels 168 and 143 can beconfigured to receive at least a portion of the second conductor 119and/or second conductor extension 180, for example.

In various embodiments, referring now to the embodiment illustrated inFIG. 21, the electrode ring 125 of the electrical ablation device 120can comprise a perimeter 150. The perimeter 150 can further comprise aninterior perimeter 151, for example. Furthermore, the electrode ring 125can comprise a tissue contacting surface 152. In various embodiments, asdescribed in greater detail herein, the electrode ring 125 can bepositioned adjacent to, against, and/or abutting tissue in a tissuetreatment region. In various embodiments, the tissue contacting surface152 of the electrode ring 125 can be configured to contact the tissue.In some embodiments, the electrode ring 125 can also comprise a groove156. As described in greater detail herein, the groove 156 can beconfigured to receive the second conductor extension 180, for example.

In various embodiments, the electrode ring 125 can comprise asubstantially or partially annular perimeter 150. In other embodiments,the electrode ring 125 can comprise a substantially circular, ellipticaland/or polygonal perimeter 150. For example, the electrode ring 125 cancomprise at least one arc, contour and/or corner around the perimeter150 thereof. In various embodiments, the perimeter 150 of the electrodering 125 can comprise a completely or substantially closed loop. Inother embodiments, the perimeter 150 of the electrode ring 125 cancomprise at least a first and second end and a gap or space positionedbetween the first and second end. In some embodiments, the electrodering 125 can comprise a plurality of gaps. Furthermore, in variousembodiments, a gap in the perimeter 150 of the electrode ring 125 cancomprise a narrow width. In other embodiments, the gap can comprise awider width. The electrode ring 125 can comprise a semi-circular shapeand can, for example, comprises a narrow gap therein. In otherembodiments, the electrode ring 125 can comprise a crescent moon shape,for example, such that the electrode ring 125 comprises a wider gaptherein.

Referring now to the embodiment illustrated in FIG. 22, the electrodering 125 can also comprise a bottom surface 154. In various embodiments,the bottom surface 154 can match and/or substantially match the contour145 in the rim 144 of cap 140 such that the electrode ring 125 issecurely received within the cap 140, for example. In variousembodiments, the contour 145 can be configured such that the electrodering 125 is substantially flush with the rim 144 of the cap 140 when theelectrode ring 125 is positioned in the contour 145, for example. Inother embodiments, at least a portion of the electrode ring 124 canextend above and/or below the rim 144 of the cap 140, for example.

Referring still to FIG. 22, the electrode ring 125 can be coupled to anenergy source 14 (FIG. 1) by the second conductor 119 and/or the secondconductor extension 180. As discussed herein, at least a portion of thesecond conductor and/or the second conductor extension 180 can extendthrough the channel 168 in the attachment number and the channel 143 inthe cap 140 such that the conductor 119 and second conductor extension180 electrically coupled the electrode ring 125 to the energy source 14,for example, in the hand piece 16 of the flexible endoscope 12 (FIG. 1).In various embodiments, the second conductor 119 can comprise aconductive wire 182 that extends from a distal portion of the secondconductor 119. In various embodiments, the conductive wire 182 canextend from the second conductor 119 to the electrode ring 125. In someembodiments, a groove 184 in a conductor extension 180 can be configuredto receive the conductive wire 182. In such embodiments, the electrodering 125 can be electrically coupled to the energy source 14 (FIG. 1)via the second conductor 119, the wire 182 and the second conductorextension 180, for example.

Referring again to the embodiment illustrated in FIGS. 4 and 5, theelectrical ablation device 120 can comprise the electrode probe 124 andthe electrode ring 125. Similar to the electrodes 24 a, 24 b, currentcan flow between the electrode probe 124 and the electrode ring 125 tonon-thermal ablate tissue therebetween. In various embodiments, thenecrotic zone or the tissue treatment region can correspond to theregion in which current flows when at least one of the electrode probe124 and electrode ring 125 is energized by an energy source 14 (FIG. 1).In various embodiments, the tissue contacting surface 152 of theelectrode ring 125 can be positioned against tissue in a tissuetreatment region. For example, the tissue contacting surface 152 can bepositioned to abut undesirable tissue 48 in the tissue treatment region.Furthermore, the electrode probe 124 can be positioned within theelectrode ring 125. In various embodiments, the tissue treatment regioncan correspond to the region between the contact surface 152 of theelectrode ring 125 and the distal end 170 of the electrode probe 125. Insuch embodiments, current conducted between the electrode probe 124 andthe electrode ring 125 can non-thermally ablate tissue therebetween.

In various embodiments, the electrode ring 125 can comprise a cathodeand the electrode probe 124 can comprise an anode such that currentflows from the electrode probe 124 to the electrode ring 125 when atleast one of the electrodes 124, 125 is energized by an energy source 14(FIG. 1). In other embodiments, the electrode ring 125 can comprise ananode and the electrode probe 124 can comprise an cathode such thatcurrent flows from the electrode ring 125 to the electrode probe 124when at least one of the electrodes 124, 125 is energized by an energysource 14 (FIG. 1). In various embodiments, the electrical ablationdevice 120 can comprise at least two electrode probes 124 positionedrelative to an electrode ring 125, for example. In such embodiments, theelectrode ring 125 can comprise a common ground or cathode for theplurality of anode electrode probes 124 positioned therein, for example.Further, current can flow from each electrode probe 124 through thetissue to the electrode ring 125, for example. Further, in variousembodiments, the surgeon, operator, or clinician can move the electrodeprobes 124 relative to the electrode ring 125 to control the tissuetreatment region treated by the electrodes 124, 125. In someembodiments, the electrical ablation device 120 can comprise a first anda second energy source. In such embodiments, the first energy source canoperably energize a first electrode probe and the second energy sourcecan operably energize a second electrode probe. In various embodiments,the surgeon, operator, or clinician can elect to draw a greater powerfrom the first energy source than the second energy source, for example.In other embodiments, the surgeon, operator, or clinician can elect todraw a greater power from the second energy source than the first energysource, for example.

The configuration of the electrical ablation device 120 relative totissue can permit the operator, surgeon, or clinician to targetundesirable tissue 48 (FIG. 2) in a tissue treatment region. In variousembodiments, as described in greater detail herein, the operator,surgeon, or clinician can target tissue in a first necrotic zone 65 a,second necrotic zone 65 b and/or third necrotic zone 65 c (FIG. 2) ofthe tissue treatment region during a surgical procedure. For example,the geometry of a necrotic zone can be controlled by the relativepositions of the electrode probe 124, the electrode ring 125, andtissue. In various embodiments, the position of the distal end 170 ofthe electrode probe 124 relative to the electrode ring 125 positionedagainst tissue can determine the necrotic zone 65 a (FIG. 2). Asdescribed in greater detail herein, when the tissue contacting surface152 of the electrode ring 125 is positioned against tissue, the distalend 170 of the electrode probe 124 can translate relative to theinterior perimeter 151 of the electrode ring 125. For example, thedistal end 170 can translate from a proximal position to a distalposition relative to the interior perimeter 151. In some embodiments,the distal end 170 can translate from a retracted position inside of thecap 140 to an extended position outside of or beyond the cap 140. Forexample, the tissue contacting surface 152 can be positioned againsttissue and the distal end 170 of the electrode probe 124 can be movedfrom the first position within the cap 140 to the second positionoutside of the cap 140. When the distal end 170 moves to a positionoutside of the cap 140, the needle tip 172 at the distal end 170 canpierce through tissue in the tissue treatment region.

In various embodiments, a necrotic zone can be controlled by thedistance between the distal end 170 of the electrode probe 124 and thecontact surface 152 of the electrode ring 125, for example, the distancethat the needle tip 172 extends into the tissue. In various embodiments,the needle tip 172 can be flush with or substantially flush with thecontact surface 152 such that the necrotic zone comprises asubstantially disk-like shape. In other embodiments, as illustrated inthe embodiments of FIGS. 23 and 24, the distal end 170 of the electrodeprobe 124 can be offset from the contact surface 125 such that thenecrotic zone comprises a substantially conical shape. For example,referring to FIG. 24, the distal end 170 of the electrode probe 124 canextend a relatively small distance D2 beyond the contact surface 152 ofthe electrode ring 125 to define a short conical necrotic zone 165 b,for example. In other embodiments, referring to FIG. 23, the distal end170 of the electrode probe 124 can be extended a larger distance D1beyond the contact surface 152 of the electrode ring 125 to define alonger conical necrotic zone 165 a, for example.

In various embodiments, the electrical ablation device 120 can beconfigured to generate a suctioning force. In some embodiments, theelectrical ablation device 120 can apply the suctioning force to tissuewhen the tissue contacting surface 152 of the electrode ring 125 ispositioned against tissue. In various embodiments, the cap 140 candirect the suction force to tissue within the inner perimeter 151 of theelectrode ring 125. The suctioning force within the cap 140 applied totissue within the inner perimeter 151 can pull, suck and/or draw tissueinto the cap 140, for example. In various embodiments, the magnitude ofthe suctioning force and/or the amount of tissue drawn into the cap 140can affect the necrotic zone treated by the electrical ablation device120.

In various embodiments, similar to electrodes 24 a and 24 b described ingreater detail herein, electrode probe 124 and/or the electrode ring 125can be repositioned during treatment to define additional necroticzone(s). In some embodiments, the electrical ablation device 120 cantreat tissue within four or more necrotic zones during a singletreatment. In various embodiments, the electrode ring 125 can be movedto abut a second area of tissue, for example. In such embodiments, thedistal end 170 of the electrode probe 124 can be withdrawn into the cap140 before the electrode ring 125 on the cap 140 is repositioned. Uponrepositioning the tissue contacting surface 152 relative to another areaof tissue, the distal end 170 of the electrode probe 124 can bere-extended into tissue. In other embodiments, the electrode ring 125can remain in the same position relative to the tissue, but the distalend 170 of the electrode probe 124 can axially and/or pivotally move.For example, the distal end 170 of the electrode probe 124 can translateaxially such that the distal end 170 extends further into the tissue todefine a longer conical necrotic zone 165 a (FIG. 23), for example. Inother embodiments, the distal end 170 of the electrode probe 124 can beretracted to define a shorter conical necrotic zone 165 b (FIG. 24), forexample. In various embodiments, the distal end 170 of the tissuetreatment region can be configured to pivot within the cap 140 relativeto the electrode ring 125. In such embodiments, the electrode probe 124can be pivoted to a different position within the necrotic zone, forexample.

As described herein, an electrical ablation device, such as electricalablation device 120, can be used in a variety of surgical procedures totreat a variety of conditions and diseases. An electrical ablationdevice can be used to transmit pulsed power and/or irreversibleelectroporation, for example, to treat Barrett's esophagus and polyps.In various embodiments, the electrical ablation device can be secured toan endoscope and can access the undesirable tissue in the tissuetreatment region through a small incision or opening. Additionalexemplary applications include the treatment of other luminal diseasessuch as, for example, tuberculosis, ulcerative colitis, ulcers, gastriccancer, and colon tumors.

What is claimed is:
 1. An apparatus for treating tissue in a tissuetreatment region, wherein the apparatus comprises: an electrode ringcomprising an interior perimeter; and an electrode probe comprising aproximal end and a distal end, wherein the distal end is structured toaxially translate relative to the interior perimeter of the electrodering, and wherein the electrode ring and the electrode probe areoperably structured to conduct current therebetween when at least one ofthe electrode ring and the electrode probe is energized by an energysource.
 2. The apparatus of claim 1, wherein the electrode ringcomprises a contact surface structured to operably abut tissue, whereinthe tissue treatment region corresponds with a zone between the contactsurface of the electrode ring and the distal end of the electrode probe,and wherein current conducted through the tissue treatment region isselected to non-thermally ablate tissue therein.
 3. The apparatus ofclaim 2, wherein the electrode ring comprises a cathode and theelectrode probe comprises an anode when the electrode probe is energizedby the energy source.
 4. The apparatus of claim 2, wherein the energysource is a Radio Frequency (RF) energy source.
 5. The apparatus ofclaim 2, wherein the energy source is a pulsed energy source.
 6. Theapparatus of claim 2, wherein the energy source is an irreversibleelectroporation energy source.
 7. The apparatus of claim 6, wherein theenergy source is a pulsed energy source.
 8. The apparatus of claim 2,wherein current conducted through the tissue treatment region isselected to generate an electric field of approximately 1500 Volts percentimeter.
 9. The apparatus of claim 1, wherein the distal end of theelectrode probe comprises a needle tip, and wherein the needle tip isstructured to operably pierce tissue when the distal end is moved from afirst position to a second position relative to the interior perimeterof the electrode ring.
 10. The apparatus of claim 1, wherein distal endof the electrode probe comprises a hook, and wherein the hook isstructured to operably draw tissue into the electrode ring when thedistal end is moved from a first position to a second position relativeto the interior perimeter of the electrode ring.
 11. The apparatus ofclaim 1, wherein the distal end is pivotable relative to the electrodering.
 12. The apparatus of claim 1, further comprising a cap having aproximal section and a distal rim, wherein the electrode ring isperipherally positioned around at least a portion of the distal rim, andwherein the cap is structured to operably apply a suctioning force todraw tissue into the cap.
 13. The apparatus of claim 12, furthercomprising a flexible shaft, wherein the proximal section of the cap iscoupled to the flexible shaft.
 14. The apparatus of claim 12, furthercomprising a conductor through at least a portion of the cap andstructured to operably connect the electrode ring to the energy source.15. The apparatus of claim 12, wherein the cap comprises a diameter, andwherein the distal rim slants across the diameter relative to theproximal section of the cap.
 16. The apparatus of claim 1, furthercomprising a temperature sensor.
 17. The apparatus of claim 16, whereinthe temperature sensor comprises a plurality of sensors, wherein atleast one sensor is positioned near the distal end of the electrodeprobe, and wherein at least one sensor is positioned on the electrodering.
 18. An electrical ablation system comprising: an energy source; ahousing that comprises a working channel and a rim, wherein the rimcomprises an electrode that comprises a substantially annular shape; anda probe moveably positioned through the working channel of the housing,wherein the probe comprises a distal portion, wherein the distal portionis structured to move relative to the rim, and wherein the distalportion of the probe and the electrode are operably structured toconduct current therebetween when at least one of the probe and theelectrode is energized by an energy source.
 19. The electrical ablationsystem of claim 18, wherein the electrode comprises a contact surfacestructured to operably contact tissue, wherein a tissue treatment zonecorresponds with a region between the contact surface of the electrodeand the distal portion of the probe, and wherein current conductedthrough the tissue treatment zone is selected to non-thermally ablatetissue therein.
 20. The system of claim 18, wherein the distal portionof the probe comprises a needle, and wherein the needle is structured tooperably pierce tissue in the tissue treatment zone when the distal endof the probe moves from a retracted position to an extended positionrelative to the rim.